The present invention relates to apparatus and to a method for removing fine particles from a liquid medium. The invention is particularly useful for removing single cell or filamentous microscopic particles in the order of up to 10 microns in diameter. One desicribed application is for removing algae growing in a solar or sludge pond, and another described application is for removing blood cells from blood.
The conventional separation techniques, such as filtering or centrifuging, are generally not efficient and/or are very expensive when used for large-scale separation of particles of microscopic size (e.g., in the order of up to 10 microns in diameter) suspended in a liquid medium. Various sonic or compressional wave techniques have been used for particle separation, but as a rule they have been used for particles much larger than microscopic size.
An objecct of the present invention is to provide novel apparatus and method for removing single cell or filamentous particles of microscopic size, in the order of up to 10 microns in diameter, from a liquid medium by ultrasonic waves.